The present invention relates to a condensate discharging device for discharging condensate produced in various kinds of equipment using steam and piping for steam, or for feeding the condensate under pressure to a boiler or an apparatus using waste heat.
Condensate condensed in equipment using steam is ordinarily discharged through a steam trap. However, in the case where the condensate is recovered to a place higher in pressure, such as a boiler or an apparatus utilizing waste heat, or in the case where the secondary pressure is higher than the primary pressure, like the case of discharging condensate within a vacuum into the atmosphere, the condensate can not be discharged using the steam trap.
In the case where the secondary pressure is higher than the primary pressure, a condensate discharging device (pumping trap) as disclosed in Japanese utility model laid-open publication sho-50-147228 is used. This device comprises a condensate receiving chamber provided with a condensate inlet opening and a condensate outlet opening, and a high pressure operating fluid (pressure gas) inlet and outlet. In the condensate receiving chamber, an open or closed type of float is set up so as to rise and drop according to the water level and is connected to an inlet valve for opening and closing the operating high pressure fluid inlet and to an exhaust valve for opening and closing the fluid outlet. Through the cooperation with respective check valves arranged at the condensate inlet and outlet openings, condensate is introduced into the condensate receiving chamber, after the operating high pressure fluid inlet is closed and the fluid outlet is opened, until the water level within the condensate receiving chamber reaches a predetermined level. When the predetermined level is reached, the operating high pressure fluid outlet is closed and the fluid inlet is opened, introducing the operating high pressure fluid into the condensate receiving chamber so that the action of pressure causes the condensate to be discharged from the opened outlet opening.
Furthermore, U.S. Pat. No. 5,141,405 discloses a device basically similar in construction to the above-described device.
Among the above-mentioned devices using steam, for example, in a heat exchanger for heating a fluid to be heated by steam, supply to the heat exchanger is carried out after the pressure of steam is controlled so as to maintain a temperature of the fluid to be heated delivered from the heat exchanger constant, which causes the primary pressure to rise to a pressure higher or fall to a pressure lower than the secondary pressure.
If the condensate discharging device disclosed in the above-mentioned utility model laid-open publication sho-50-147228 or U.S. Pat. No. 5,141,405 is mounted on such a piece of equipment using steam, a problem arises in that when the primary pressure rises to a pressure higher than the secondary pressure, the check valve arranged at the condensate outlet is always caused to be opened so that not only the condensate but also the steam under high pressure is flown out therethrough. Meanwhile, if an ordinary steam trap is mounted on such a device using steam, it will not be able to be used in the case where the primary pressure is lower than the secondary pressure.